Development of Rock-Based Geopolymers for Oilwell Cementing Applications—Utilizing Brazilian Rock Precursor

This article focuses on developing and characterizing one-part rock-based geopolymer slurries using Brazilian rock precursors for well construction and plugging and abandonment (P&A) applications. The study presents the fluid-state and solid-state properties of these geopolymers, as well as X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM), to understand the microstructure of the precursors and the reaction level. The effect of temperature and pressure on the development of compressive strength was investigated. By altering these parameters, the study aimed to examine the impact of various conditions on the strength development of the geopolymer material. Technological tests were conducted following API RP 10B-2. Compressive strength tests were conducted to determine early strength development and thickening time. Post-curing Rietveld refinement by XRD was performed to examine the microstructure and reactivity. Finally, fluid-state properties were also assessed, including thickening time and viscosity. The strength development of geopolymers is observed to be time- and temperature-dependent, as shown by UCS results. The final product has a dense structure, and its long-term performance will require evaluation to determine its sealing capability and volume change as a barrier material. The results highlight the novelty of employing locally available Brazilian rock precursors in one-part geopolymer formulations and provide a scientific basis for their potential application as sustainable alternatives to conventional cements in well construction and abandonment.